Rapid advances in nanotechnology have brought about the realization of material films that may comprise only as little as a few atomic layers. For example, semiconductors and metals of sub-10 nm thicknesses have been realized. Then, the graphene paradigm inspired a plethora of other 2D and quasi-2D materials. In this new era, materials have transcended beyond the traditional thin films to a domain of atomic-scale thicknesses, unleashing vast and unexplored possibilities for light-matter interactions. This Optical Materials Express virtual issue features a collection of thirty-five papers aiming to capture the current state-of-the art, trends and open research directions in photonics with ultrathin and atomically thin materials
